Merge remote-tracking branch 'refs/remotes/origin/cryo2ice' into cryo2ice

Author: mikala-nsidc

notebooks/cryo2ice/cryo2ice_utils.py

@@ -0,0 +1,79 @@
+"""Utility routines to download CryoSat-2 files"""
+
+import os
+import platform
+from ftplib import FTP
+import sys
+from typing import Union, List
+
+from pathlib import Path
+
+
+def get_padded_count(count, max_count):
+    return str(count).zfill(len(str(max_count)))
+
+
+def file_byte_handler(data):
+    global download_file_obj, read_byte_count, total_byte_count
+    download_file_obj.write(data)
+    read_byte_count = read_byte_count + len(data)
+    progress_bar(read_byte_count, total_byte_count)
+
+
+def progress_bar(progress, total, prefix="", size=60, file=sys.stdout):
+    if total != 0:
+        x = int(size * progress / total)
+        x_percent = int(100 * progress / total)
+        file.write(f" {prefix} [{'='*x}{' '*(size-x)}] {x_percent} % \r")
+        file.flush()
+
+
+def download_files(user_email: str, esa_files: List[str], dir: Union[str,Path]="."):
+    """Downloads CryoSat-2 Files from ESA ftp
+
+    Arguments
+    ---------
+    user_email : email to use for anonymous ftp login
+    esa_files : list of paths to cryosat-2 files
+    dir : output directory path.  Default is current working directory.
+          If dir does not exist it is created.
+
+    Returns
+    -------
+    list of paths to downloaded files
+    """
+    global download_file_obj, read_byte_count, total_byte_count
+
+    if not isinstance(dir, Path):
+        dir = Path(dir)
+        
+    if not dir.exists():
+        if not dir.exists():
+            print("Download path dir does not exist.  Creating dir")
+            dir.mkdir(parents=True, exist_ok=True)
+
+    print("About to connect to ESA science server")
+    with FTP("science-pds.cryosat.esa.int") as ftp:
+        try:
+            ftp.login("anonymous", user_email)
+            print("Downloading {} files".format(len(esa_files)))
+
+            download_path_list = []
+            for i, filename in enumerate(esa_files):
+                padded_count = get_padded_count(i + 1, len(esa_files))
+                print("{}/{}. Downloading file {}".format(padded_count, len(esa_files), 
+                                                           os.path.basename(filename)))
+
+                download_path = dir / os.path.basename(filename)
+                with open(download_path, 'wb') as download_file:
+                    download_file_obj = download_file
+                    total_byte_count = ftp.size(filename)
+                    read_byte_count = 0
+                    ftp.retrbinary('RETR ' + filename, file_byte_handler, 1024)
+                download_path_list.append(download_path)
+                print("\n")
+        finally:
+            print("Exiting FTP.")
+            ftp.quit()
+
+    return download_path_list